/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.alibaba.metrics;

import java.io.OutputStream;

public interface Snapshot {

    /**
     * Returns the value at the given quantile.
     *
     * @param quantile    a given quantile, in {@code [0..1]}
     * @return the value in the distribution at {@code quantile}
     */
    double getValue(double quantile);

    /**
     * Returns the entire set of values in the snapshot.
     *
     * @return the entire set of values
     */
    long[] getValues();

    /**
     * Returns the number of values in the snapshot.
     *
     * @return the number of values
     */
    int size();

    /**
     * Returns the median value in the distribution.
     *
     * @return the median value
     */
    double getMedian();

    /**
     * Returns the value at the 75th percentile in the distribution.
     *
     * @return the value at the 75th percentile
     */
    double get75thPercentile();

    /**
     * Returns the value at the 95th percentile in the distribution.
     *
     * @return the value at the 95th percentile
     */
    double get95thPercentile();

    /**
     * Returns the value at the 98th percentile in the distribution.
     *
     * @return the value at the 98th percentile
     */
    double get98thPercentile();

    /**
     * Returns the value at the 99th percentile in the distribution.
     *
     * @return the value at the 99th percentile
     */
    double get99thPercentile();

    /**
     * Returns the value at the 99.9th percentile in the distribution.
     *
     * @return the value at the 99.9th percentile
     */
    double get999thPercentile();

    /**
     * Returns the highest value in the snapshot.
     *
     * @return the highest value
     */
    long getMax();

    /**
     * Returns the arithmetic mean of the values in the snapshot.
     *
     * @return the arithmetic mean
     */
    double getMean();

    /**
     * Returns the lowest value in the snapshot.
     *
     * @return the lowest value
     */
    long getMin();

    /**
     * Returns the standard deviation of the values in the snapshot.
     *
     * @return the standard value
     */
    double getStdDev();

    /**
     * Writes the values of the snapshot to the given stream.
     *
     * @param output an output stream
     */
    void dump(OutputStream output);
}
